Sezonske promjene kondicijskoga i gonadosomatskog indeksa Carassius gibelio u parku prirode Kopački rit, Hrvatska

This study’s objective was to explore some of the annual Prussian carp’s (Carassius gibelio) biological characteristics (sex ratio, length–weight ratio, and gonado somatic index - GSI) in the Kopački Rit Nature Park in Croatia. The Prussian carp is an invasive fish species originated from Asia, which became widely distributed throughout Europe and is believed to be responsible for a decline in the number of indigenous fish, invertebrate, and macrophyte populations in different areas. The fish sampling was conducted from September to November 2017 and from February to July 2018, respectively, using electrofishing. A total of 475 fish individuals were caught and measured for the total length, standard length, body height, and body weight. Males made up 34.31% of the population of Prussian carp. The mean value of Fulton condition factor (FC) of Prussian carp in Kopački Rit was 1.77 ± 0.28. Overall, the FC value had a relatively small amplitude, but it exhibited a clear seasonal vari ability. The average GSI values of females (9.91 ± 5.34) were higher than those of males (3.58 ± 1.37) during the observed period. The average GSI values indicate that the majority of females are spawning in the late April and May, which are also the same periods when other cyprinid species are spawning, allowing the Prussian carp to exploit its gynogenesis strategy.Cilj ovoga istraživanja bila je istražiti neke od bioloških karakteristika (omjer spolova, dužinsko-maseni odnos i gonadosomatski indeks) babuške (Carassius gibelio) tijekom jedne godine u Parku prirode „Kopački rit“ u Hrvatskoj. Babuška je alohtona vrsta ribe uvezena iz Azije koja se od tada proširila diljem Europe te se vjeruje kako je odgovorna za opadanje autohtone populacije riba, beskralježnjaka i makrofita u pojedinim područjima. Ihtiološko uzorkovanje obavljeno je od rujna do studenoga 2017. te od veljače do srpnja 2018. s pomoću elektroribolova. Ukupno je ulovljeno 475 jedinaka, na kojima je izmjerena ukupna dužina, standardna dužina, visina tijela i masa. Mužjaci su činili 34,31 % populacije babuške. Prosječna vrijednost Fultonova kondicijskog faktora (FC) za babušku u Kopačkome ritu bila je 1,77 ± 0,28. Sveukupno, vrijednosti FC-a su imale relativno malo varijacija, ali ukazuju na jasnu sezonsku varijabilnost. Prosječne vrijednosti gonado-somatskoga indeksa (GSI) za ženke (9,91 ± 5,34) bile su veće negoli za mužjake (3,58 ± 1,37) tijekom promatranoga razdoblja. Prosječne vrijednosti GSI-ja ukazuju kako se većina ženka mrijesti krajem travnja i tijekom svibnja, što je isti period kada se mrijeste i ostale ciprinidne vrste, a to babuški omogućuje da se koristi svojom strategijom ginogeneze

Utjecaj hranidbenog režima na preživljavanje šaranskih mladunaca tijekom testa na salinitetni stres - kratko priopćenje.

Experiments were carried out on common carp (Cyprinus carpio L.) larvae in a recalculating aquatic system for a period of 21 days. Four feeding variants with different transition times from live (nauplii of Artemia salina) to artificial feed (Biomar larviva) were examined. The greatest average total length (25.72 ± 3.37 mm) and weight (213.81 ± 105.52 mg) was achieved by common carp larvae fed over the whole period with nauplii of the brine shrimp (group D). A significantly higher (P<0.05) final bodyweight was reported in group D in comparison with groups A and B. Survival in groups B, C and D was high (81.53, 84.14, 80.66% respectively) but not in group A (32.44 - 43.36%) with the earliest transition to artificial feed. A salinity stress test was carried out on the final day of rearing. Common carp fry survival in the salinity stress test was analyzed using the Kaplan - Meier test. High significant differences (P<0.001) have only been reported between feeding treatments at 14‰ salinity level.Istraživanja su provedena na ličinkama šarana (Cyprinus carpio L.) u uzgojnim uvjetima recirkulacijskog sustava u trajanju 21 dan. Promatrana su četiri hranidbena režima s različitim prijelazima sa žive hrane (naupliji artemije, Artemia salina) na umjetnu hranu (Biomar larviva). Najveću prosječnu dužinu tijela (25,72 ± 3,37 mm) i masu tijela (213,81 ± 105,52 mg) ostvarile su ličinke šarana hranjene čitavo vrijeme nauplijima artemije (A. salina) u skupini D. Značajno signifikantna (P<0,05) završna tjelesna masa utvrđena je u skupini D u odnosu na skupine A i B. Najveći postotak preživljavanja utvrđen je u skupinama B, C i D (81,53; 84,14; 80,66 %), dok je u skupini A s najranijim prijelazom na umjetnu hranu postotak preživljavanja znatno manji (32,44 - 43,36 %). Test na salinitetni stres proveden je zadnjeg dana uzgoja. Preživljavanje mladunaca šarana tijekom salinitetnog stresa analizirano je Kaplan-Meierovim testom. Statistički značajna razlika (P<0,001) utvrđena je između hranidbenih režima samo pri salinitetu od 14‰

NOVI NALAZ CRNKE (Umbra krameri Walbaum 1792) U HRVATSKOJ

Distribution of the European mudminnow, Umbra krameri, Walbaum 1792, in Croatia is scarce with only few confirmed localities. In order to confirm presence of the European mudminnow in amelioration canal network along the Drava River an electrofishing was conducted in the small Mlinski canal. Ten specimen of European mudminnow were caught During sampling. Using ImageJ software a truss network was constructed between landmark points on photographs of caught specimens. Total body lengths of caught European mudminnow ranged from 61 to 100 mm (72.00±11.52 mm) whereas standard one ranged from 52 to 85 mm (60.30±10.08 mm). Body weight were relatively small ranging from 1.81 to 7.59 g (3.80±1.89 g), while the Fulton condition factor ranged from 0.76 to 1.23 (0.96±0.15). This new locality of the European mudminnow is situated about 50 km downstream from the last confirmed site in Croatia.Informacije o distribuciji crnke, Umbra krameri Walbaum 1792, u Hrvatskoj su oskudne, uključujući svega nekoliko potvrđenih lokaliteta. U svrhu potvrđivanja prisutnosti crnke u mreži melioracijskih kanala u blizini rijeke Drave, obavljeno je uzorkovanje ribe elektroagregatom na Mlinskome kanalu. Tijekom uzorkovanja ulovljeno je 10 primjeraka crnke. Korištenjem računalnoga programa ImageJ razvijena je metoda razgranate mreže na fotografijama ulovljenih crnki. Ukupna dužina ulovljenih crnki bila je od 61,00 do 100,00 mm (72,00±11,52 mm), a standardna dužina iznosila je od 52,00 do 85,00 mm (60,30±10,08 mm). Ukupna tjelesna masa bila je relativno mala, u rasponu od 1,81 do 7,59 g (3,80±1,89 g), dok je Fultonov kondicijski indeks iznosio od 0,76 do 1,23 (0,96±0,15). Ova nalazište crnke u Hrvatskoj smješteno je oko 50 km nizvodno od zadnjega potvrđenog lokaliteta uz tok rijeke Drave

The lichen flora of Risnjak National Park (Croatia)

This paper lists 80 lichen taxa recorded for Risnjak National Park. Among the listed species, Candelariella reflexa, Chaenotheca brunneola, Placynthiella icmalea, Usnea diplotypus and Usnea subfloridana have been already first reported for Croatia. The field survey was carried out at 14 collection sites in the periods 1997–1998 and 2001–2002. Floristic composition, life form spectrum and substrate preferences are described. The most numerous genera are Cladonia, Pertusaria, Lecanora and Peltigera. Lichens growth on 16 various substrates, among which the deciduous trees, Acer pseudoplatanus and Fagus sylvatica dominate. The alliance Lobarion pulmonariae, consisting of some rare and old-forest indicator species, is present within the area

The lichen flora of Risnjak National Park (Croatia)

This paper lists 80 lichen taxa recorded for Risnjak National Park. Among the listed species, Candelariella reflexa, Chaenotheca brunneola, Placynthiella icmalea, Usnea diplotypus and Usnea subfloridana have been already first reported for Croatia. The field survey was carried out at 14 collection sites in the periods 1997–1998 and 2001–2002. Floristic composition, life form spectrum and substrate preferences are described. The most numerous genera are Cladonia, Pertusaria, Lecanora and Peltigera. Lichens growth on 16 various substrates, among which the deciduous trees, Acer pseudoplatanus and Fagus sylvatica dominate. The alliance Lobarion pulmonariae, consisting of some rare and old-forest indicator species, is present within the area

Dietary Habits of the Golden Jackal (Canis aureus L.) in the Eastern Croatia

In the past fifteen years, a considerable increase in size of the golden jackal (Canis aureus) population has been recorded in the eastern part of Croatia. Dietary habits have been determined in the period 2008-2011 by analysing the content of 238 stomachs. Golden jackal is typical omnivorous and opportunistic forager which consumes easiest accessible food, according to season and habitat, primary animal food, such as carcasses, rodents and meat waste. Parts of big game animals were found consumed in the period of main hunting season during the winter. Small animals were frequently present in the diet during the spring and summer, in the season of breeding and cub-rearing. Meat waste originated from livestock has been consumed periodically, during the pig slaughtering season at rural households. Plant material occurred occasionally in diet of the golden jackal, depending on time of crop harvest or ripening of fruits. There is no conflict between golden jackal and sectors of livestock and agriculture in the eastern Croatia

BODY AND REPRODUCTIVE CONDITIONS OF RED DEER YOUNG HINDS (CERVUS ELAPHUS L.) IN THE HUNTING GROUND PODUNAVLJE-PODRAVLJE (BARANJA REGION, CROATIA)

Cilj istraživanja bio je utvrditi međusobni odnos tjelesnih i reproduktivnih svojstava dvizica jelena običnog u ekološkim uvjetima ritsko-močvarnih staništa. Istraživanje je provedeno tijekom pet lovnih godina (2004./05. do 2008./09.) na 62 dvizice u državnome lovištu XIV/9 Podunavlje – Podravlje u Baranji u istočnoj Hrvatskoj. Kod dvizica je nakon odstrjela utvrđivana neto tjelesna masa te prisutnost fetusa u maternici. Najviše vrijednosti neto tjelesne mase ostvarene su tijekom 2007./08. i 2008./09 godine. Statistička značajnost (P<0,05) utvrđena je u odnosu između 2007./08. s 2005./06. i 2006./07. Srednja vrijednost neto tjelesnih masa gravidnih dvizica indikativno je veća u odnosu na neoplođene jedinke (gravidne 66,13 kg; negravidne 50,71 kg). Utvrđena je i statistički značajna korelacija između neto tjelesne mase i oplodnje. Veća tjelesna masa kod dvizica u prirodi može biti pokazatelj graviditeta, što je važno pri uzgojnoselekcijskome radu kod ženskih grla. Povoljni klimatski i hidrološki uvjeti tijekom lovnih 2007./08. i 2008./09. godina rezultirali su iznadprosječnom tjelesnom razvijenosti teladi, odnosno dvizica, što je preduvjet za bolja reproduktivna svojstva ženki i trofejnu strukturu mužjaka.The aim of the study was to determine inter-relation between body and reproductive conditions of young hinds of red deer living in the environmental conditions of wetland habitats. The research was carried out during the five hunting years: 2004/05 – 2008/09, on 62 young hinds in the hunting ground XIV/9 Podunavlje - Podravlje, situated in Baranja region of the eastern Croatia. Net body weight and presence of foetus in the womb were determined after the game culling. The highest net body weight was achieved during 2007/08 and 2008/09. Statistical significance (P<0.05) was confirmed in relation between years 2007/08 and 2005/06 and 2006/07. Mean net body weight of the pregnant young hinds is indicatively higher than of the non-pregnant hinds. Correlation between net body weight and fertilization is statistically significant (pregnant 66.13 kg; non-pregnant 50.71 kg). Favourable climatic and hydrological conditions during the hunting years 2007/08 and 2008/09 resulted in the above average body development of calves and young hinds, which is the requisite for reproductive conditions improvement in females and trophy potential in males

ATTENDANCE OF SUNFLOWER (HELIANTHUS ANNUUS L.) BY HONEY BEE (APIS MELLIFERA L.) IN AGRO-ECO SYSTEM OF BARANJA COUNTY

Istraživanje prikazuje posjećenost suncokreta medonosnom pčelom (Apis mellifera carnica) a obavljeno je na poljskom pokusu u slučajnom blok rasporedu koji je obuhvatio 6 hibrida merkantilnog suncokreta (Helianthus annuus L.), najviše zastupljenih na poljima kontinentalne Hrvatske. Mjerenje se provodilo na 100, 200 i 300 metara od košnica. Tijekom mjerenja uočena je različita atraktivnost pojedinog hibrida u pokusu za medonosnu pčelu. Statističkom je analizom utvrđena signifikantna razlika između hibrida H2, kod kojeg je utvrđena najmanja posjećenost, i hibrida H4 kod kojeg je ona bila najveća. Nadalje, analiza podataka je pokazala da je najmanja posjećenost pčelom bila na udaljenosti 200 m od košnica. Na udaljenostima 100 i 300 metara nije bilo veće razlike. Ujedno je bio uočen vrlo mali broj prirodnih oprašivača, što je indikator znatnog smanjenja njihove populacije u agro-eko sustavu Baranje. Tijekom cvatnje suncokreta medonosna pčela zabilježena je kao najzastupljeniji oprašivač. Evidentirana je u 99,53 % mjerenja obavljenih tijekom pokusa, bumbari (Bombus spp.) su evidentirani u 0,32 % mjerenja, dok je muha Volucella zonaria (Poda, 1761) evidentirana u 0,15 % mjerenja. Klimatske prilike tijekom cvatnje suncokreta bile su pogodne za aktivnost pčele (temp. 19,9 - 27,5 °C, relativna vlažnost zraka 65-88% i 16,1 mm oborina tijekom tri dana).The current research investigates attendance of sunflower (Helianthus annuus L.) by honeybee (Apis mellifera L.). The research was conducted in a field experiment in random block arrangement which included 6 most represented hybrids of mercantile sunflower on fields of continental Croatia. Measurement was conducted at 100, 200 and 300 meters distance from beehives. During the investigation different attractiveness of each hybrid for honeybee was observed. Statistical analyses showed statistically significant difference between the hybrid H2, which was the least attended, and the hybrid H4, which was the most attended. Data analysis also showed that honeybees attended the least sunflowers which were 200m distant from hives. At 100 and 300 m distance no statistically significant differences were found. Honeybee was estimated as the most represented pollinator of sunflower during the blooming period: it was recorded in 99.53% of measurement; bumblebee (Bombus spp.) was recorded in 0.32% of measurement, while the fly Volucella zonaria was recorded in 0.15% of measurement. Very small number of natural pollinators observed is an indicator of significant decrease of their population in the agro-eco system of Baranja County

ASSESSMENT METHODS OF CORMORANT (Phalacrocorax carbo) DIET

Različite metode procjene hranidbe kormorana služe za procjenu njihova dnevnog obroka kako bi se iz tih i drugih podataka procijenila šteta koju kormorani čine na gospodarskim ribnjacima, kao i na otvorenim vodama. Svi parametri koji služe u procjeni šteta na ribljem fondu koju čine kormorani (broj ptica, gustoća i struktura riba, svakodnevni obrok, cijena ribe, stupanj zaštite i očuvanja i sl.) specifični su za pojedini ribnjak ili neki drugi akvatorij i ne mogu se primijeniti drugdje, osim na tom lokalitetu. Rezultati o najnižim i najvišim vrijednostima mase riba koju na dan konzumira kormoran višestruko variraju. Pregledom dostupne literature utvrđene su sljedeće vrijednosti za odrasle jedinke: gvalice — 347 g, gvalice zarobljenih ptica — 371 g, želučani sadržaj — 359,5 g, regurgitacija — 260 do 539 g, energijske potrebe — 751 g, temperatura želuca — 336±98 g.Various cormorant diet assessment methods are used to assess their daily meal in order to evaluate, using these and other data, the damage to commercial fish farms as well as the damage on open waters caused by cormorants. All of the parameters used for evaluating the damage to fish stock (number of birds, density and fish structure, daily meal, fish price, degree of protection and preservation etc.) are specific for an individual fishpond or other body of water and can only be used for that locality and not elsewhere. The results on the lowest and highest values of fish mass that cormorants eat daily vary extensively. By examining the available literature, the following values for individual adults have been determined: pellets — 347 g, pellets of captive cormorants — 371 g, stomach content — 359.5 g, regurgitations — 260 to 539 g, energy requirements — 751 g, stomach temperature — 336±98 g

COMMERCIAL FISHERIES ON THE DANUBE IN THE REPUBLIC OF CROATIA ANALYZED BY THE FOX AND SCHAEFER MODEL

Za analizu gospodarskog ribolova Foxovim i Schaeferovim modelom na rijeci Dunavu u Republici Hrvatskoj, u razdoblju 2004. – 2009. godine, korištena je službena evidencija ulova Ministarstva poljoprivrede, Uprave ribarstva. U promatranom razdoblju prosječan godišnji ulov ribe na Dunavu iznosio je 39.088,05 ± 7.450,06 kg. Broj odobrenih i realiziranih povlastica bio je u rasponu od 19 do 25, od 30 mogućih. Utvrđen je visok udio ribara (32,28 ± 7,55 %) koji nisu dostavili potpune podatke o ostvarenom ulovu i korištenim ribolovnim alatima, iako im je to zakonska obveza. Ulov po jedinici napora (CPUE) imao je velike oscilacije u promatranom razdoblju te prosječno iznosi 0,985 ± 0,290 kg•alat•sat-1. Foxov i Schaeferov model maksimalnog održivog ulova ribe u Dunavu ukazuje na relativno nisku ribolovnu kvotu (42,0 – 44,0 t) od predviđene (101,9 – 130,5 t). Radi boljeg ribolovnog gospodarenja Dunavom bilo bi potrebno pojačati edukaciju i kontrolu i ribara i ribiča, kao i osnovati zajedničko tijelo s Republikom Srbijom.Official data of the Ministry of Agriculture, Directorate of Fisheries was used in order to analyze commercial fishing on the Danube in the Republic of Croatia between 2004 to 2009 (average annual catch was 39,088.05 kg ± 7,450.06 kg. The number of approved and used licenses varied between 19 and 25, out of a possible 30. A high percentage of fishermen (32.28 % ± 7.55 %) who ignored the legal obligation to deliver full data on the catch and tools used was determined. Catch per unit effort (CPUE) varied greatly with an average of 0.985 ± 0.29 kg • tool hour-1. The Fox and Schaefer models of maximum sustainable yield in the Danube indicate relatively low fishing quota (42.0 – 44.0 t) in comparison to the anticipated (101.9 – 130.5 t). In order to improve fishery management, it is necessary to enhance the education and control of recreational and commercial fishermen, as well as to form a joint administrative body with the Republic of Serbia